The present invention relates to a new and distinct variety of Buddleja (butterfly bush) grown as an ornamental shrub for home and commercial landscapes. Butterfly bush is typically grown for its attractive, fragrant flowers that are borne throughout the growing season.
The new and distinct variety of butterfly bush resulted from a formal breeding program established by the inventors in Raleigh, N.C., United States. One of the objectives of the breeding program was to develop a semi-compact, spreading Buddleja with pendant flowers. ‘Purple Haze’ was selected in Jackson Springs, N.C. in 2005 from a population of 231 seedling progeny derived from a hand pollinated cross of ‘Miss Ruby’×(‘Honeycomb×(‘Nanho Purple’×Buddleja lindleyana)) made in 2004 in Raleigh, N.C. ‘Miss Ruby’ (U.S. Plant Pat. No. 19,950) was released in 2008. It is described as a compact upright plant with bright pink flowers. ‘Honeycomb’ (unpatented) was released in 1997, and is described as a hybrid of Buddleja davidii and Buddleja globosa. ‘Nanho Purple’ (unpatented) is a semi-compact selection of Buddleja davidii var. nanhoensis. Buddleja lindleyana is a species native to China, but used in garden settings. All four parents are available in commerce.
The seeds resulting from the 2004 controlled hybridization process were harvested in fall of 2004 and germinated in Raleigh, N.C. in the winter of 2005. The resulting 231 seedlings were planted in field trials in spring of 2005 at Jackson Springs, N.C. These plants flowered in summer 2005, and one plant, designated NC2005-29, was selected for its compact growth habit, mounding and spreading habit, large attractive purple-violet flowers, pendant flower panicles, and lack of seed set (female sterile). This original plant demonstrated characteristics identical to those subsequently expressed on other plants when propagated from stem cuttings. This single plant is the subject of the present invention Buddleja ‘Purple Haze’.
The distinguishing traits of ‘Purple Haze’ are semi-compact growth habit, mounding spreading growth, gray-green leaf color, large purple-violet flowers that are arranged in arching panicles, and female sterility. The cultural requirements for ‘Purple Haze’ are well-drained soil, full sun, and moderate moisture. ‘Purple Haze’ exhibits no serious pest or disease problems known to the inventors, except for occasional spider mite infestation during periods of hot, dry weather.
The closest comparison known to the inventors is the species Buddleja lindleyana (no named cultivars in commerce). Plants and flowers of this new variety differ from Buddleja lindleyana. In direct comparisons of ‘Purple Haze’ and Buddleja lindleyana in the inventor's experimental trials, plants of ‘Purple Haze’ are consistently more compact, more highly branched, more dense, have larger flower panicles, and produce less viable seed than Buddleja lindleyana. ‘Purple Haze’ is distinctly different from its female parent, ‘Miss Ruby’. ‘Miss Ruby’ has upright growth and is considerable taller than ‘Purple Haze’. After two growing seasons, average height in replicated trials was 72 and 106 cm for unpruned plants of ‘Purple Haze’ and ‘Miss Ruby’, respectively.
The first asexual propagation of ‘Purple Haze’ was conducted by the inventors in fall 2005 in Raleigh, N.C., and ‘Purple Haze’ has subsequently been propagated in the same location in years 2006 and 2007. In all cases, the original plant selection was propagated asexually by softwood to semi-hardwood stem cuttings. Such cuttings root readily under mist in about 14 to 21 days, and resume normal growth. Fifteen plants derived from stem cuttings of the variety were established in test plots in Jackson Springs, N.C. and two plants were established in Raleigh, N.C. in 2007. During all asexual propagation, the characteristics of the original plant have been maintained. Plants derived from stem cuttings exhibit characteristics identical to those of the original plant, and no aberrant phenotypes have appeared.
Test plantings and performance evaluation over five years at Jackson Springs and Raleigh, N.C. demonstrate this variety to be relatively consistent in its characteristics even under the different growing conditions associated with yearly climatic variation.
Plants of the new variety are moderately vigorous after establishment in the field, being less vigorous and more compact than most cultivars of butterfly bush. Young plants have averaged about 0.4 meters of growth per year. Plants are spreading and mounding in growth habit. Flowering occurs in the first year of growth on newly formed wood. The inflorescence is an arching panicle, and shows a purple-violet flower color. Flowering usually begins in early June in Jackson Springs, N.C., and continues throughout the growing season until the first freeze event in October or November. An individual inflorescence flowers for about 10-14 days, depending on temperature, but new flowers are made during the entire growing season. Female fertility of flowers is very low, and the new cultivar sets virtually no seed in a field or landscape setting, an asset in landscape plantings.
‘Purple Haze’ is distinguished from other related known cultivars based on the unique combination of traits including compact habit, spreading mounding growth, pendant purple-violet flowers, and female sterility.
The new variety has been named the ‘PURPLE HAZE’ cultivar. First public offer for sale of ‘Purple Haze’ was made by Spring Meadow Nursery, Grand Haven, Mich., U.S.A. on Aug. 1, 2010, but no sale of plants has yet taken place at the time of application.